And he will urge Americans to be on alert for the possibility of new terrorist strikes and patient as the military effort unfolds, administration officials say.

On Monday, Bush plans to attend the swearing-in of the new director of homeland security, former Pennsylvania Gov. Tom Ridge. Vice President Dick Cheney is slated to administer the oath of office.

Ridge takes the new position at a time that U.S. officials are on "high alert" in anticipation that terrorists might respond to the U.S.-led strikes in Afghanistan by launching new attacks on U.S. targets.

The president must first sign an executive order creating the new Cabinet-level position.

It has gone through several drafts because of the debate over the specific powers Ridge will have to force changes at the more than 40 government agencies with roles either in responding to or trying to prevent terrorist acts.

"It hasn't been easy" to get agreement on the language of the order, a senior official involved in the effort said Sunday night.

A second official said that "the president understands the challenge ahead." The official said in the days after the first wave of strikes, "it will be imperative to remind people this will be a long effort."

This official said the Ridge swearing-in offered an opportunity to reassure Americans that the government was doing all it could to try to head off any additional terrorism in the United States, and make clear Americans have a responsibility to be on the alert themselves for suspicious activity.